Used Car Catastrophe - Constant Problems

I’m glad you got it fixed! Weak ignition can be hard to diagnose. With weak ignition the misfires get worse as the throttle is increased. High RPM and low load will work best. CEL must have been coming on due to misfires. In your case it must be that the coil doesn’t build enough energy inside it to make a strong spark once the engine exceeds a certain speed. After a little bit the engine warms up and it is able to speed up.

If the over heating issue isn’t solved, it could be that the radiator passages are clogged. I don’t think an ignition problem would have anyhting to do with that, or the pinging problem.

(I want to say that I really appreciate everyone’s experience, thoughts, help, and replies!)

Since the replacement of the coolant it seems to handle going up mountains better, still gets a bit warm but so far it hasn’t been reaching overheating levels. I’m hoping the replacement of the coolant / cap is enough to just keep it together for the next ~1.5 months, after which point we’re gonna sell it.

It made it up and through the Tavildara Pass today. 2316 starting point to 10689 feet at the highest point.

In a vehicle that has–so far–been quirky and unreliable, and with emergency road assistance largely unavailable?

You’re much more adventurous than I am!